MANCHESTER, N.H. — Mitt Romney ended the Republican primary here with a flourish, pronouncing himself ready to lead a nation.

Seeking to unify both Republicans and the country, Romney delivered a 15-minute address that was heavy on rhetoric and light on policy proposals. He offered familiar criticisms of President Barack Obama with signature syrupy paeans to Americana while offering the quadrennial challenger’s question: Are you better off now than you were four years ago?

“Is it easier to make ends meet?” he said to the call-and-response chant of “No!” “Is it easier to sell your home or buy a new one? Have you saved what you needed for retirement? Are you making more in your job? Do you have a better chance to get a better job? Do you pay less at the pump?”

The winner of Connecticut, Delaware, Pennsylvania and Rhode Island and New York, Romney mimicked the catchphrase from the last challenger (Bill Clinton) to unseat an incumbent president (George H.W. Bush).

“If the answer were ‘yes’ to those questions, then President Obama would be running for reelection based on his achievements, and rightly so,” Romney said. “But because he has failed, he will run a campaign of diversions, distractions, and distortions. That kind of campaign may have worked at another place and in a different time. But not here and not now. It’s still about the economy” — here he paused for effect — “and we’re not stupid.”

With the primary basically over, Romney made unifying shout-outs to single mothers, grandparents, business owners, “urban children” and people struggling on public assistance.

He called America “fundamentally fair,” but didn’t mention his proposal to cut marginal income tax rates by 20 percent. Social issues, so key to the Republican primary, were entirely absent from his remarks. Instead, the focus was on the economy and the country’s general direction.

“Americans have always been eternal optimists,” he said. “But over the last three-and-a-half years, we have seen hopes and dreams diminished by false promises and weak leadership. Everywhere I go, Americans are tired of being tired, and many of those who are fortunate enough to have a job are working harder for less.”

While he touted conservative ideas like stripping labor unions of some organizing rights and expanding school choice programs, Romney never used the word — conservative — that identified the Republican voters with whom he struggled during the four grueling months of primaries and caucuses.

Instead, Romney told the hotel ballroom crowd here and the national cable-television audience that it’s time for a new beginning.

“Tonight is the start of a new campaign to unite every American who knows in their heart that we can do better,” Romney said. “The last few years have been the best that Barack Obama can do, but it’s not the best America can do. Tonight is the beginning of the end of the disappointments of the Obama years and it’s the start of a new and better chapter that we will write together. This has already been a long campaign, but many Americans are just now beginning to focus on the choice before the country.”

Forty-four years after his father’s presidential run ended in a loss to Richard M. Nixon and four years after Romney lost the GOP primary to Sen. John McCain, Romney delivered a biography to a new general election audience, looping from his father’s up-by-the-bootstraps story to his own history of founding successful companies, name-checking national chain stores in communities across the country.

“You might not have heard that our business helped start other businesses, like Staples and Sports Authority and a new steel mill and a learning center called Bright Horizons,” he said. “And I’d tell you that not every business made it and there were good days and bad days, but every day was a lesson. And after 25 years, I know how to lead us out of this stagnant Obama economy and into a job-creating recovery.”

And while his riff on “the economy, stupid” harked back to Bill Clinton’s 1992 win over George H.W. Bush, Romney’s big finish was more reminiscent of Bob Dole’s 1996 promise to build a “bridge to the past.”

“There was a time — not so long ago — when each of us could walk a little taller and stand a little straighter because we had a gift that no one else in the world shared,” he said. “We were Americans. That meant something different to each of us, but it meant something special to all of us. We knew it without question. And so did the world.”

He continued: “Those days are coming back. That’s our destiny. We believe in America. We believe in ourselves. Our greatest days are still ahead. We are, after all, Americans.”